So imagine Guido’s surprise when it appeared Prentis got litigious on the Mail on Sunday:

“Last Sunday we said that Dave Prentis, the Unison general secretary, had secured a 31 per cent increase to his pension contributions from the union. This was incorrect. In fact as a member of the Unison staff pension scheme, Mr Prentis is paying the increase himself under the union’s ‘salary sacrifice’ scheme. We apologise to Mr Prentis for our mistake and for any distress caused.”

The Mail were close, but not quite there. The question they should have been asking is why should someone who is a member of a very generous union final salary scheme choose to sacrifice yet more money to pay into the scheme?

Well a good place to start in the hunt for an answer is Unison’s own Annual Report. Specifically page 16. You won’t be surprised to see that comrade Prentis is one of those unfortunate fat-cats who earn between £100,000 and £112,950. Someone on that money is subject to Gordon’s personal allowance tapering. This means his marginal rate of tax was 60%.

Rather than pay this rate of tax though, Prentis has engaged in some personal tax avoidance and paid the money into his pension, ensuring the state couldn’t get its hands on it. By doing so he has effectively got a 60% tax relief on those payments. Because the Unison financial year doesn’t match the fiscal year, its not possible to say exactly what Mr Prentis’s pay in 2010/2011 was, but Guido understands that it was not more than £99,999…

Only a fool would go out of his way to pay more tax and many up and down the country use this same technique to minimise their bill. However what if you scaremonger about this sort of behaviour for cheap political points? Five days ago Prentis said:

“The Government would be better advised to look at plugging tax loopholes for the rich and tackling tax evasion that costs us billions, rather than giving top earners a cash break.”

Did you have any particular “tax loopholes for the rich” in mind Dave?